A polyurethane foam is produced from polyol and polyisocyanate as main raw materials, and obtained by mixing a foaming agent, a foam stabilizer, a catalyst, a colorant, and the like with polyurethane and resinifying the resultant mixture while foaming it, and is widely used particularly in the field of automobile as a seat cushioning, a door trim, a headrest, an armrest, a steering wheel, a sound absorbing or vibration damping material for bottom, top and the like, a cushioning material, a sun visor, and the like. A tertiary amine compound used as a catalyst is an indispensable substance in the resinification for a polyurethane foam and the reaction of foaming or expansion, but the amine catalyst has been known to slowly volatilize from the polyurethane foam after produced to cause other interior parts to suffer discoloration or whitening.
Further, in the field of automobile, in an attempt to reduce the burden on the environment and improve the production efficiency, studies are made on interior trim parts having no coating (coating-less), and a coating-less material which does not require a coating treatment intended for surface protection is desired. Therefore, such a coating-less material needs an amine resistance.
A polycarbonate resin has excellent transparency, impact resistance, heat resistance, and dimensional stability, and therefore is used as engineering plastics in a wide variety of fields, such as housing for electric or electronic device, interior or exterior automotive trim parts, building materials, furniture, instruments, and miscellaneous goods. Further, the polycarbonate resin has a low specific gravity, as compared to inorganic glass, and can be reduced in weight, and has excellent productivity, and therefore is used in the application of window for automobile and the like.
Further, a sheet or film using a polycarbonate resin is subjected to additional fabrication, such as a coating treatment, a laminate, or surface decoration, and the resultant material is widely used as various types of display devices and protective parts for interior automotive trims.
However, a polycarbonate resin which has not been subjected to coating treatment has a problem in that, when exposed to a basic environment containing an amine, the polymer is decomposed, so that the surface of a molded article obtained from the resin suffers whitening, leading to poor appearance. Further, such a polycarbonate resin has a pencil hardness as low as 2B, as measured in accordance with Testing methods for paints—Part 5: Mechanical property of film—Section 4: Scratch hardness (Pencil method), which is descried in JIS K5600-5-4, and has a problem in that when used as a coating-less material, the surface of the material is likely to be scratched.
For solving the problems, the use of a copolymerized polycarbonate resin having a high surface hardness (for example, PTL 1) has been known. This copolymerized polycarbonate resin has a high surface hardness and excellent resistance to ammonia; however, it has a problem of poor impact resistance.
Further, there is a description of a method for obtaining a polycarbonate or copolycarbonate having 2,2-bis(4-hydroxy-3-methylphenyl)propane as constituent units (for example, PTL's 2 to 6). This polycarbonate resin has an improved surface hardness, but has a problem in that it has poor heat resistance, as compared to other polycarbonate resins.
Thus, there has not yet been present a polycarbonate resin which is excellent in scratch resistance, impact resistance, heat resistance, and amine resistance.